Finding the Fourth Proportional to 2,105.22, 3,158.43 and 872.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,105.22 : 3,158.43 = 872.70 : x
2. Step 2: Convert to fraction form
   2,105.22/3,158.43 = 872.70/x
3. Step 3: Cross multiply
   2,105.22x = 3,158.43 × 872.70
4. Step 4: Simplify right side
   2,105.22x = 2,756,361.86
5. Step 5: Solve for x
   x = 2,756,361.86/2,105.22
6. Step 6: Final answer
   x = 1,309.30